墨尔本PTE素材库——Fuel Efficient Engines Have a Sooty Flaw

墨尔本PTE素材库——Fuel Efficient Engines Have a Sooty Flaw

中文批注

一种新燃料的发明无疑，将会带动新一轮的燃料经济，但同时，也会带来更严重的碳排放。这条Podcast就燃料经济的增长是否真的会导致剧烈的气候变化进行讨论。

澳大利亚语言学院整理的墨尔本PTE素材库，旨在帮助各位PTE考生整理一些可以用作PTE考试题型练习的素材，可以帮助大家提升dictation、re-tell lecture、Summarize  spoken text 等等题型的能力哦！PTE市面上的素材并不多，练习的题目也不多，所以AIL整理的这些PTE素材库，真的是帮助非常大的哦！

就比如，这是一段很好的re-tell lecture以及summarize spoken/ Written Text的练习素材。大家可以尝试复述这段Podcast的内容，主要关注的问题就是：the differences between two injections 。

【Key Vocabulary】

Sooty adj. 乌黑的

Flaw n. 缺陷，瑕疵

Black carbon emission 黑色碳排放

Creep up 上升

Injection n. 注射

Turbocharge 用涡轮给增压

Cylinder n. 圆柱体

Emit vt. 发出

Aromatic adj. 芳香泾

Compound n. 化合物

Paradoxically n. 自相矛盾地

Full Transcript

A newer type of fuel injection offers better fuel economy, but paradoxically increases black carbon emissions—meaning a pollution trade-off. Christopher Intagliata reports. 

If you’ve gone shopping for a car lately, you might have noticed that fuel economy—the number of miles per gallon—is creeping up. One reason is a more efficient type of fuel injection, called gas direct injection. It’s a feature of half the new cars sold in the U.S. last year.

“With that kind of engine design you can also introduce turbocharging—that’s really what it comes down to: more engine power with a smaller engine.” Naomi Zimmerman, an air-quality scientist at Carnegie Mellon University—who has never owned a car. “Probably because I did a whole PhD on engine emissions.”

Here’s how the two injection methods differ. In the old standard, called “port fuel injection,” gas is injected into the air intake, where it mixes with air before hitting the cylinder. In direct injection though, as the name implies, the fuel is injected directly into the cylinder. It’s more fuel efficient, meaning lower CO2 emissions, which will help slow climate change. But paradoxically, it also emits more particulate matter, including black carbon, or soot—a pollutant implicated in global warming.

Zimmerman and her colleagues analyzed studies of direct injection engines to see how this pollution tradeoff works out for the climate. “The answer is that it’s really complicated and it’s not certain.” But on average, she says, boosting fuel economy five to nine percent would probably cancel out the warming effects of black soot, and score a net positive for the climate. The findings are in the journal Environmental Science and Technology. [Naomi Zimmerman et al., Assessing the Climate Trade-Offs of Gasoline Direct Injection Engines]

The fuel economy goal might be different in places with big temperature swings, and where gasoline has more aromatic compounds—which seem to boost black carbon emissions. One place that fits the bill: Canada. “There we might need to be closer to the 10 percent, 15 percent mark in terms of improving fuel economy. Which is actually a very aggressive increase in fuel economy.”

She says one solution that might reduce black carbon emissions is gasoline particulate filters. Which would also screen out particulate matter dangerous to human health. Meaning a win for the planet—and the people who live on it.

(source: http://www.scientificamerican.com/podcast/episode/fuel-efficient-engines-have-a-sooty-flaw/)